The cells of the inner wall of Schlemm's canal in monkeys have been found to show changes in the number of pinocytotic vesicles under conditions of different pressures. We now propose to expand on this finding to see if it can be done by changing pressure hydrostatically while treating the eye with miotics, adrenalin derivatives and steroids and following the intracellular changes, and the passage of electron microscopically opaque material. In addition to this further anatomical changes in the emerging buphthalmic rabbit population will be evaluated, as the colony expands.